The present disclosure relates to an improved modular system which provides multiple options for interchangeably mounting a night vision device to headgear such as a tactical or military field helmet and a firearm. The system herein provides multiple options for a monocular or binocular night vision device, multiple flip options for moving an attached night vision device between a viewing position when the device is in use on a helmet and a stowed position out of the user's line of sight when the viewing device is not in use. The system herein is also adapted to provide multiple options for moving a night vision device in and out of the optical axis of a weapon-mounted scope or sight when used on a weapon. The system according to this disclosure is particularly suited for use with night vision devices that enable viewing under nighttime or other low light conditions, such as a night vision goggle (NVG) device or enhanced night vision goggle (ENVG) device, although it will be recognized that the system herein could be adapted for use with other optical, opto-electronic, or electronic viewing devices.